Studies will be conducted to further our understanding of the molecular mechanism of genetic recombination. Biochemical analyses of possible intermediates of recombination as well as investigations into their biological activity via a transformation system, will be undertaken. Three model systems are proposed to study the different mechanisms of recombination that may occur in E. coli. These studies will be carried out with special emphasis on the Rec pathways which may be involved. Effort will be made to develop a cell free recombination system. The possible effect of transcription on the process of recombination will also be studied.